Whenever Raiders owner Al Davis gets around to officially naming Hue Jackson his new head coach, he might let us know who the new defensive coordinator is.

The Raiders are not bringing back defensive coordinator John Marshall, according to league sources. Marshall has been with the team for two years, and though Oakland improved last season, Davis will not be renewing Marshall's contract, which is up Tuesday.

When asked about Marshall being let go, Raiders senior executive John Herrera said the team had staff evaluations last week and that they are confidential.

Rob Ryan, the Raiders' defensive coordinator from 2004 to 2008, has talked to Davis about returning but seems to be on the verge of signing with the Cowboys. They offered him a contract and the defensive coordinator job Friday night, but as of press time Saturday night, he hadn't signed.

Letting Marshall go again shows Davis' unhappiness with an 8-8 finish. It was Oakland's best record in eight years, but two days after the season, the Raiders announced they were not picking up the option on head coach Tom Cable's contract. The Chronicle reported Jan. 4 that Davis would name offensive coordinator Hue Jackson the new coach, and indications are that could finally happen this week.

Under Marshall, Oakland was ranked 11th in yards per game allowed (322.8) and 13th in points per game allowed (23.2). But they had trouble stopping the run, ranked 29th for the second straight season. The Raiders also gave up more than 30 points in a game six times this season, the most since they did it seven times in 2004.

Defensive tackle Tommy Kelly often described the defensive efforts as "Stop, stop, boom" - the 29 touchdown passes it allowed were 13 more than in 2009.

Marshall, 65, has been an NFL assistant for 31 years, and a defensive coordinator for five teams. He drew up the defenses for Atlanta (1983-85), San Francisco (1997-98), Carolina (1999-2001), Seattle (2006-08) and Oakland.

While with the Niners, he won two Super Bowl rings - he was defensive line coach there from 1989 to '93, linebackers coach from 1994 to '96 and defensive coordinator from 1997 to '98. He also has a national championship ring from when he was linebackers coach at USC in 1978.